Deimos
by Tiara of Sapphires
Summary: Deimos: one of the two moons of Mars, named after the Greek god of terror and dread. Or: if the Alex/J'onn sparring scene at the beginning of "Solitude" went very differently.
**Basically a 'what-if' from Episode 1x15 "Solitude".**

 **Because when that sparring scene came on screen, my shipper brain started screaming. And there can never be too few shameless PWPs of any ship.**

 **Enjoy!**

 **Disclaimer: I do not own Supergirl or any of its characters, this is for my own personal enjoyment or whatever blah blah blah.**

In hindsight, it was probably not the smartest ideas on Alex's part to do this: sparring with Hank… _J'onn_. Not after recent events. Kara and the Black Mercy. Killing Astra.

Astra. Killing Kara's aunt was simultaneously her biggest regret and… _not_. She was saving J'onn from being executed. Alex would have had to watch him die if she did not do something. But letting him take the blame for her death, allowing Kara to be so angry with him, she definitely regretted that. She felt so guilty over it.

She was…emotionally compromised. She could feel it with each hit she dealt, a frantic, bottled-up energy that needed to come out.

It had been a few days since Kara left the DEO and something felt off-kilter and Alex did not like it. Not at all. She was angry with herself for letting this happen.

J'onn rolled with the punches, literally. It was either his legitimate fighting strategy or he was making sure she did not accidentally break her hand on his face. Alex was not sure if that was possible, but neither of them seemed to be eager to find out.

It was cathartic for the two of them: a controlled environment where no one dared bother them and they could hone their skills, using each other.

Alex struck, he dodged. J'onn struck, she dodged. It was obvious that he was not trying to get any solid hits on her. She knew that if he wished it, she would be flat on her back with a broken nose in a second.

She pushed him back to the edge of the raised platform. Alex's fist collided with the side of his face, enough to send him down the platform to hit the nearby wall. She was close behind, ready to finish the fight, nervous energy twitching through her.

She swiped at him, a right hook that might have left a mark, but he grabbed her arm as she struck out, pulling her forward as he pushed away from the wall.

In one smooth motion, their positions were flipped, Alex's back hitting the concrete. J'onn's arm was a solid line, pressed against her collarbone and pinning her. He was using his Martian strength, enough that she could feel discomfort, but not enough to hurt.

His dark eyes glimmered bright red, almost teasingly.

It was over. He had her pinned and there was no way she was going to break his hold. That fact should have made her uncomfortable, especially having her boss's face only inches from hers, both of them gasping for breath. She should have been tapping out.

And yet…there was something that felt headier than the energy that always carried whenever they sparred together, enough to make her heart race harder than before.

It did not help that he was not moving away either, their eyes locked together, the thread of tension pulled taut between them.

Alex was not sure what to do at this impasse that they found themselves at, heat rising from her chest and closing around her throat. Halfway between their normal professional relationship and something very different.

She leaned forward, his arm loosening its press against her collarbone in response. He was pulling away from her, as if he thought the moment had ended.

Unconsciously, she reached forward and grabbed two fistfuls of his shirt, his stupid, near skin-tight shirt. He froze, looking at her with confusion.

It was not like she showed anything other than platonic, professional interest before. But it was likely latent inside her, and this was just the catalyst. Before Alex could allow herself to reconsider, unwilling to let this… _something_ to slip away, she pulled J'onn towards her, or maybe she was pulling herself towards him.

And she kissed him, her eyes fluttering closed.

Alex heard him inhale sharply and she could imagine the look of shock on his face, his entire body a stiff line. His lips were full and dry, nothing and everything like she expected.

She was warm, spiked with adrenaline, and she knew she made a mistake, something that she should not have indulged in at all. But he was not moving away, not moving at all, not pulling away immediately like she thought. It told her nothing about what he thought. She did not know.

After a few moments, blissful and tense as the were, Alex broke away and opened her eyes, ready to take what was to come. J'onn stared at her, stunned confusion in his eyes.

Then, J'onn took her face in his hands, the pads of his fingers rough and calloused against her cheeks. Alex gasped at the contact and the fact that he was touching her, the veil of professionalism between them torn apart. They stared at each other in wonder for a moment, calm before the storm, and he kissed her, his tongue running along the seam of her lips.

The dam broke between them in a mess of lips, tongue, and teeth, one trying to consume the other.

He pressed close to her, until there was only clothing between the lines of their bodies. Victory and arousal simmered in her veins. She did not make the bone-headed move of the century. He wanted her just like she wanted him. He wanted her.

 _He_ wanted _her_.

An understanding passed between them and there was a flurry of hands, fingers digging into skin, grasping and searching. The world shifted under Alex's feet as she searched and felt with a freedom that she had not experienced before. Seconds, minutes passed as they staked their claims on their partner's bodies.

Her jacket was in a puddle at her feet- she did not know when that happened- and J'onn's mouth found the space where her neck and shoulder met. She tilted her head to give him easier access and he obliged, sucking a mark into her pulse point.

"Dammit, J'onn," she whispered, knowing that she was going to have to cover that up when this was over.

Alex ran her hands under his shirt, taut muscles jumping under her ministrations. They roamed across his back, her nails running faint lines over his skin.

If she was trying to douse the fire that had been growing inside her for the past week, it was not working. If anything, it was making it worse, a raging blaze that threatened to burn her from the inside out.

Kisses were good. Touching was good. But it was not enough. It would probably never be enough. She needed more from him. The question was if he was as willing as she was.

She took his hand in hers, resting it on her chest and pushing it down where she needed to be touched most, leaving his palm spread just under the slope of her stomach. The heat from his skin seeped through the thin fabric of her tank top and she just hoped that he caught her drift that she wanted him to do something.

J'onn caught her gaze and his eyes glowed red again. Alex blushed at the sight, not off-put by the not-very-subtle reminder that he was not human. This was J'onn, she trusted him.

He slipped his hand under the waistband of her pants, down into the space between her thighs. A reedy cry - quiet, they had to be quiet - escaped her lips as the tips of his fingers stroked her clit.

"J'onn—you," she sputtered.

Alex arched forward to press his forehead against his collarbone, a finger pressing inside of her. She was already wet for him, so his finger slid in easily. He stroked in and out of her, loosening her up.

He pressed in another finger and Alex tried not to ride his hand, trying to keep to measure of control. She kissed the bare skin she could reach, mouthing and nipping as he pumped his fingers into her.

"Alex," he breathed as she sucked a matching mark just behind his ear.

He crooked his fingers and her knees buckled as pleasure shot up her spine. The only thing keeping her from crashing to the ground his strong arm around her waist.

"You are lucky I heal quickly or we will both be in trouble," he whispered hot in her ear.

His fingers crooked again, moving faster, sending her closer to the edge.

"Please," Alex whispered. She was not sure what she was asking him to do, what she wanted him to do. Anything, everything.

It was good, he made her feel so good, but it was not enough, never enough. So she grabbed his wrist, halting his movements immediately.

"Wait," she croaked, still shivering from the sensation.

J'onn looked at her questioningly and she gained her nerve.

"I want—I want you. All of you."

He pulled his hand away and she swallowed a keen at the loss.

"Are you sure?" he asked, ever concerned about her well-being.

It was Alex's turn to move her hand southward, groping the hardened bulge in his exercise pants. Her reward was a punched-out grunt from J'onn, dark eyes blown out in arousal, his grip around her waist tightening.

It had been a while, Alex had to admit that. Between her sister and her job, she did not have a lot of opportunities to be intimate with another person. How long had it been for him since he did something like this? Years, probably.

"Is that your final answer?" he huffed.

Alex rolled her eyes, her hand pressing more firmly against him, stroking downwards, relishing in the soft moan it elicited. "What do you think, J'onn? I need _you_."

For a brief moment, hesitation flickered across his face and Alex was sure he was going to spout reasons on why they should not go through with this.

Then his hands went to the hem of his shirt and she knew what his answer was.

She toed off her shoes and shucked off her pants and underwear with shaking hands as he pulled off his shirt and pushed his pants down his hips, exposing his hardened dick.

Alex felt heat rush to her face and between her legs at the sight. They were both ready.

"I'm on the pill," she burst out as an afterthought.

J'onn laughed at that, shaking his head. "I don't think Martians and humans are compatible in that way."

Alex nodded with a breathy laugh and he was on her in an instant. Her back hit the wall again, a little more gently this time. He wrapped his arm around her waist, the other around her upper thigh, the lines of their bodies fitting together, skin against skin. And he lifted her like she weighed nothing. Her legs locked around his torso on instinct, her core pressing against his length. Alex almost bit through her lip at the feeling.

Through the haze, Alex realized that there were probably more practical places for them to do this. Lying on the flat space of the sparring floor. Anywhere that wasn't at work. Not with her legs around J'onn's waist and her back pressed against a concrete wall.

But the idea of fucking in the shadows of the training room, out in the open and not at the same time, the idea of him being able to pick her up and move her around as he pleased...

"Come on, come on," she breathed, too hot, skin too tight.

Alex almost came at the feeling of him at her entrance, her heart racing. He sank into her, inch after inch, ragged breathing filling the room.

They gasped in unison when he bottomed out, Alex keening softly as he stretched her open.

She dug her fingers into his sweat-slicked back, trying to ground herself so she did not fall apart right then. And she pressed a line of kisses along the curve of his shoulder, gentle as J'onn searched for the right angle, the right pace.

Finally, he started moving in earnest, her hips moving in answer. His fingers dug into her hips, probably enough to bruise. She did not care. Her nails were leaving half-moons and raised lines in his skin, marking him as hers.

This was not going to take long, both of them already halfway there by the time their bodies joined. There would be time for slow and thoughtful, memorizing every inch of each other's skin. At least, she hoped there would be.

Suddenly, he picked up the pace, skin slapping against skin, and all Alex could do was clutch at his shoulders, muffling her gasps and moans into his mouth and against the pillar of his neck.

She was close, so close.

Either she said it aloud or J'onn was reading her mind, because immediately he stroked where their bodies were connected, angling his thrusts so she was seeing stars. The fact that they were at work -her mind was barely lucid enough to remember- stopped her from screaming his name as pleasure tingled up her spine.

Just enough, just the right amount of pressure, and she shuddered with a cry as her orgasm rippled through her.

He kissed her breathless, swallowing the little noises that she could not help but make, as his rhythm faltered. She tightened around him and J'onn made a sound halfway between a groan and a growl. He spilled inside of her, her name on his lips.

They rode the aftershocks together, clutching at each other.

Slowly, he lowered her to the ground, still connected, still breathing each other's air.

Alex touched her forehead to his, knowing that soon they would have make themselves presentable, go into the world like this never happened. A moment of intimacy, before reality set in again.

"Take me to dinner, when our shifts are over," she breathed.

J'onn nodded.

"Of course."

 **Thank you so much to Juulna for looking this over! You are da best!**

 **Please, any and all feedback is appreciated! And I will take requests for this ship!**

 **Cheers!**

 **~Tiara of Sapphires**


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